Refrigerating apparatus



Feb. 16, 1937. M. w. FISH ET AL Re. 20,268

REFRIGERATING APPARATUS Original Filed Jan. 29. 1933 2 Sheets-Sheet 1 Feb. 16, 1937; M. w. FISH El AL Re. 20,268

REFBIGERATING APPARATUS- Original Filed Jan. 29, 1950 '2 Sheets-Sheet a 65' g as 4 "-4: 4 t 79 794 I 7 7'0 75 7/ I 69 I E 6/ I H T' 1 v Reissues! Feb. 1a, 1931 UNITED STATES PATENT OFFlC hio, 'assignors, by mesne assignments, to General Motors Corporation, a corporation of Delaware Original No. 1,883,891, dated October 25, 1932,

Serial No. 424,333, January 29, 1930. Application for reissue August 30, 1934, Serial No.

142,140 2 Claims.

This invention relates to refrigerating apparatus and more particularly to a self-soldering circuit breaking device for use in refrigerating apparatlis.

Among its objects this invention contemplates the construction of an improved, rugged, efllcient and easily assembled circuit breaking device having but few parts.

A further object of this invention is to provide 10 a self-soldering device wherein a coil is arranged in heat-exchange relation with the shaft carrying a part of the locking mechanism, which coil, upon the passage of excessive current, is adapted to heat the shaft to melt the solder to release the u said locking means.

Further objects and advantages of the present -iinvention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the 20 present invention is clearly shown.

In the drawings: Fig. l .is a diagrammatic showing of a refrigcrating system with the switch and circuit breaking device shown in elevation;

Fig. 2 is a top plan view of the circuit breaking device shown in Fig. 1;

Fig. 3 is a top plan view of a modified form of circuit breaking device;

Fig. 4 is a view in section taken on the line Fig. 5 is a top plan view of a second modified form of circuit breaking device, and

Fig. 6 is an enlarged view in section taken on 45 the evaporator it through the conduit I! by the compressor ll wherein it is compressed and discharged into the condenser ft. The compressed refrigerant is liquefied in the condenser I either by the cooling eflect of air or the cooling effect of water and is collected in liquid form in the receiver I! from where it passes in liquid form to the evaporator IS. The evaporator I2 is of the type wherein the inlet is controlled by a float valve responsive to a certain level of liquid 55 refrigerant therein. This type of evaporator is disclosed in the patent to R. G. Osborn, 1,556,708, patented October 13, 1925.

The compressor ii is driven by an electric motor I! through themedium 'of the belt and pulley connection I! and the motor is connected to a source of power through the lead lines "and 2|.

In the operation of a refrigerating apparatus of this type it is desirable to maintain the evapo rator within certain predetermined limits of temperature. This may be accomplished, as herein disclosed, by means of a switch generally indicated at 22 for starting and stopping the motor It at predetermined high and low pressures respectively. This switch has not been shown in detail for the reason that the details thereof form no part of the present invention. Such details have been disclosed in an application of Otto M. Summers, Serial No. 281,599, filed May 30, 1928, and reference thereto is hereby made for a more complete description thereof. In this case it is sufllcient to state that the switch comprises a stationary contact 22, a movable contact 24, a link 25, and a lever 25 connecting the link 25 and the lever 21, said lever 21 being pivoted at its left hand end at 28 and at its right hand end being provided with a cam surface 29 adapted to engage the surface of the pivoted link 20. A bellows 3 I, the interior of which is in communication with the evaporator through the conduit 32 is operatively connected at its upper end to the lever 21. All the various parts of.the switch enumerated are suitably mounted on a supporting base.

In operation, an increase in pressure within the evaporator l2 corresponding to an increase in temperature therein, will cause the bellows 3| to expand, thereby lifting the lever 21 and causing the right hand cam surface 29 to ride over the surface III to snap the contact 24 into engagement with the contact 23. As the pressure within the evaporator decreases, due to the action of the compressor, the bellows 2| will contract and at the predetermined low pressure will cause a reverse movement of the lever 21 to disengage th contacts 22 and 24. i

To prevent injury to the motor, due to exces- L hous ng 34 provided with a removable front panel and with lugs 85 for attaching the housing to the frame supporting the switch or to any other supporting structure. Terminals 38 are mounted on the exterior rear face of the housing 34 by means of the bolts 36a passing through the housing, which bolts also secure on the inside face of the housing, the contacts 31. A plate '38, pivoted at 39' to a rearwardly extending lug 4| within the housing, carries on its under face the two contacts 42 and 43 connected by a wire 55. A ratchet 44 is supported on the upper side of the plate by means of a shaft to which the'ratchet 44 is soldered, which shaft passes through and is secured to the plate.' On the underside of the plate 38 the shaft is surrounded by the wire 55 connecting the contacts 42 and 43. A spring 46, carrying 'the pawl 41, is secured to the rear face of the housing as at 48', the pawl 41 being adapted to engage the ratchet 44 to hold the plate in the position shown in Fig. 2. Pivoted to' the plate 38 is a lever 48 carrying the lug 5| extending through an opening in the front wall of the housing. This lever engages a stop member carried by the plate ll so as to impart movement to the plate when the lug BI is pushed inwardly. The lever 48 also carries a laterally extending lug l2, which,'on lateral movement of the lug ii and lever 48, is adapted to engage theextremity of the spring 46 to disengage the pawl 41 from the ratchet 44. This provides manually operative means for interrupting the flow of current through the contacts so that the device disclosed may also be used as an ordinary switch as well as; safety switch. Also it should be noted that by providing the lug i! on the lever 48, the same means that is utilized to set the switch or cutout device, may also be used to open the switch manually.

In operation, the ratchet 44 is soldered to the shaft 45. The lug 5| is pushed inwardly, causing the lever 48 to engage the stop member ill on the plate. This movement of the lug II will cause the plate 38 to rotate counter-clockwise about its pivot point 39 and will bring the contacts 31 into engagement with the contacts 42 and 43. The pawl 41 will engage the ratchet 44 to hold the contacts in engagement. Current. will now flow through the contacts and the cutout device will remain closed as long as the current flowing remains normal. An abnormal flow of current will cause a heating of the connection between the contacts 42 and 43. Heating of this connection 55 will cause a heating of the shaft 45 which in turn will melt the solder holding the ratchet to the shaft 45. Melting of the solder will allow the ratchet 44 to rotate on the shaft 45, allowing the plate to rotate in a clockwise direction under the influence of the spring contact 31. This movement will disengage contact 31 from contact 43/ breaking the circuit therethrough. As soon as the current stops, the solder will again cool and solidify, whereby the plate may again be locked in position. If at any time it is desired to break the circuit, the lever 48 may be moved laterally by the lug 5|, causing the lug 52 to engage the spring 48 to disengage the pawl 41 from the ratchet 44-.

The salient features of this cut-out device are the providing of the heating coil around the shaft or in any other position to cause a slight heat lag; that is to say to provide means whereby a period of time will elapse between the heating of the wire 55 and the melting of the solder. Another is the provision of the same means for Referring to Figs. 3and 4, this modified form I comprises the housing provided with lugs 6|. Terminals 62 and 63 are provided on the rear face of the housing and aresecured thereto by the screws 64 and 65 passing through the housing, which screws also secure the contacts 66 and 61 within the housing. A plate 69 is slidably mounted within the housing and carries on its rear face the contacts 10 and 1| connected by the wire 11. The contacts 10 and 1| are adapted to engage the contacts 66 and 61 and are adapted to be locked in the position shown in Fig. 3. This locking means comprises a ratchet 13 soldered on to a shaft 14, which shaft is Journaled in the lug 15 secured to the plate 69. An extension 18 secured to the front wall of the housing and. passing through'a slot 16a in the plate 69, supports one end of a spring 11 which, at its other end, is attached to an extension 18 secured to the movable plate 69. The extension 1| also. has soldered to its outer end a spring clip 19, providing a pawl for engaging the ratchet 13.

The plate 89 is provided with an operating handle comprising an externally threaded rod 80 secured to the plate 8! and passing through an elongated slot 8| in-the front panel of the housing. A knob 82 is threaded on the rod 80 whereby the movement of the rod laterally in the slot II will cause movement of the-plate 0!.

In operation overheating of the shaft 14 caused by excessive current flowing through the wire 12 will cause a melting of the solder securing the ratchet 13 e shaft 14 and will allow the ratchet 13 to rotate, and the plate OI will move to the left under the influence of the spring 11, thus breaking the contacts. Breaking of the contacts will allow the solder to again cool and solidify, whereby the device may be reset by moving the plate" to the right as indicated in Fig. 8.

It should be noted that this modification also embodies theheat lag between the heating coil and soldered Joint.

A third modification has been disclosed in Pig. 5. This modification is similar in many respects tothatshowninl lga3and4. Inthiscasea movable plate 90, carrying the contacts II and 92 which are connected by a wire 93 surrounding the shaft 94 of a pinion 98, is adapted to move under the influence of the spring I. to disengage the contacts SI and 92 from the stationary contacts 91 and 98.

In normal operation, the pinion is solderedto the shaft 84 and, the plate is held in the position shown in Figure 5, with the contacts II and I! engaging the contacts 91 and 98 by means of the pawl 99 engaging the ratchet pinion 95. Upon excessive current flowing through the wire 03, the solder. holding the ratchet pinion 9! on the shaft 94 will melt, which will allow the ratchet pinion to rotate and consequently the plate III will move under the influence of the spring 0! to dis engage the contacts.

This modification, it will be noted also includes the 'heating coil surrounding the shaft carrying the ratchet and constitutes another form of cutout device in which there is provided a lag between the heating coil and the soldered ioint.

lnallol'themodiflcationathestructureis comparatively simple, easy to assemble and disassemble and contains the minimum number of parts and contacts. In all the modifications, the locking means or part thereof is carried by the movable member. In addition, all 01 the modiiications disclose the heating coil out of engagement with the soldered Joint to provide a slight heat lag therebetween.

While the form of embodiment oi the invention as herein disclosed constitutes a preferred form. it is to'be understood that other forms might be adopted, all coming withinthe scope of the claims which follow.

What is claimed is as follows:

1. A circuit breaking device comprising a contact, a movable member, a second contact carried by said movable member, means for locking said 1 movable member in position so that said second contact ensaa'es said iirst contact, means for moving said member in locking position, thermallyactuated means for releasing said locking means upon excessive flow of current through said contacts, one 0! said contacts comprising spring means for snapn s open said contacts upon the release of said locking means, said moving means also comprising means for manually releasing said locking means substantially as described.

2. A thermally perable circuit breaker comprising a self-opening switch, an electric heater connected in circuit with said switch, a heat conductor, a latchilxed upon said conductor by a fusible binder and adapted to be released by heat conducted by said conductor from said heater to said binder to fuse the same, a catch to engage said latch and hold said switch closed, and a single manually operated means to close said switch and engage said catch with said latch and operable by pressure exerted upon its outer end at anangletoitsaxistoreleasesaidcatchirom said latch.

HORTILIER W. FISH. HARRY I. CLARK. 

